A Burning Splint Will Burn More Vigorously in Pure Oxygen

A burning splint will burn more vigorously in pure oxygen than in air because

A) nitrogen is a reactant in combustion and its low concentration in pure oxygen catalyzes the combustion.
B) nitrogen is a product of combustion and the system reaches equilibrium at a lower temperature.
C) oxygen is a reactant in combustion and concentration of oxygen is higher in pure oxygen than is in air.
D) oxygen is a catalyst for combustion.
E) oxygen is a product of combustion.